This invention relates generally to electrical interconnections. Specifically, the present invention concerns devices which are used in making electrical interconnections between circuitry located on opposing sides of a wall having a sealed opening. In addition, the present invention relates to electrical interconnection devices which utilize flexible printed wiring.
Flexible printed wiring may be made of copper clad Kapton. Kapton is a commonly used insulating material manufactured by DePont made of polyimide plastic. However, flexible printed wiring may use other types of insulating material, such as nylon. Flexible printed wiring exhibits many desirable features. It is easily used in a manufacturing environment, and adapts to wave soldering. Thus, it obviates the need for measuring, cutting, stripping, and hand soldering wires in the making of electrical interconnections. Accordingly, in many situations flexible printed wiring represents a highly desirable alternative to using standard insulated wire cables.
Various feedthrough techniques are known for routing electrical signals through a wall of a sealed container. However, these techniques are generally not readily adaptable to flexible printed wiring cables. One known feedthrough technique utilizes conductive lugs which project beyond opposing sides of a header. The conductive lugs are environmentally sealed within the header, and the header is environmentally sealed within an opening in the housing wall. However, wires must be soldered to the conductive lugs at the opposing sides of the header, then the wires must be prepared and routed to various sources and destinations of electrical signals. Thus, this technique fails to achieve the advantages which can be achieved through the use of flexible printed wiring cables. Furthermore, the soldering required at the conductive lugs heats the header and risks damaging the seal between the conductive lugs and the header. Accordingly, this technique increases the labor, rework, and cost of making the electrical connections between sources and destinations of electrical signals.
Other techniques for achieving a sealed feedthrough utilize a header which contains several parts. Typically, individual wires of a cable reside at predetermined positions within the header, various parts of the header mate together, and then these header parts are clamped together to maintain an environmental seal. While this type of electrical feedthrough provides some of the advantages that may be achieved through using a flexible printed wiring cable, it tends to be overly complicated, and therefore excessively expensive.